<HTML>
<BODY BGCOLOR="white">
<PRE>
<FONT color="green">001</FONT>    /*<a name="line.1"></a>
<FONT color="green">002</FONT>     * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a>
<FONT color="green">003</FONT>     * contributor license agreements.  See the NOTICE file distributed with<a name="line.3"></a>
<FONT color="green">004</FONT>     * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<FONT color="green">005</FONT>     * The ASF licenses this file to You under the Apache License, Version 2.0<a name="line.5"></a>
<FONT color="green">006</FONT>     * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<FONT color="green">007</FONT>     * the License.  You may obtain a copy of the License at<a name="line.7"></a>
<FONT color="green">008</FONT>     *<a name="line.8"></a>
<FONT color="green">009</FONT>     *     http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<FONT color="green">010</FONT>     *<a name="line.10"></a>
<FONT color="green">011</FONT>     * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<FONT color="green">012</FONT>     * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<FONT color="green">013</FONT>     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<FONT color="green">014</FONT>     * See the License for the specific language governing permissions and<a name="line.14"></a>
<FONT color="green">015</FONT>     * limitations under the License.<a name="line.15"></a>
<FONT color="green">016</FONT>     */<a name="line.16"></a>
<FONT color="green">017</FONT>    package org.apache.commons.jxpath.servlet;<a name="line.17"></a>
<FONT color="green">018</FONT>    <a name="line.18"></a>
<FONT color="green">019</FONT>    import javax.servlet.ServletContext;<a name="line.19"></a>
<FONT color="green">020</FONT>    import javax.servlet.ServletRequest;<a name="line.20"></a>
<FONT color="green">021</FONT>    import javax.servlet.http.HttpServletRequest;<a name="line.21"></a>
<FONT color="green">022</FONT>    import javax.servlet.http.HttpSession;<a name="line.22"></a>
<FONT color="green">023</FONT>    import javax.servlet.jsp.PageContext;<a name="line.23"></a>
<FONT color="green">024</FONT>    import org.apache.commons.jxpath.JXPathContext;<a name="line.24"></a>
<FONT color="green">025</FONT>    import org.apache.commons.jxpath.JXPathContextFactory;<a name="line.25"></a>
<FONT color="green">026</FONT>    import org.apache.commons.jxpath.JXPathIntrospector;<a name="line.26"></a>
<FONT color="green">027</FONT>    <a name="line.27"></a>
<FONT color="green">028</FONT>    /**<a name="line.28"></a>
<FONT color="green">029</FONT>     * Static methods that allocate and cache JXPathContexts bound to<a name="line.29"></a>
<FONT color="green">030</FONT>     * {@link PageContext}, {@link ServletRequest}, {@link HttpSession}<a name="line.30"></a>
<FONT color="green">031</FONT>     * and {@link ServletContext}.<a name="line.31"></a>
<FONT color="green">032</FONT>     * &lt;p&gt;<a name="line.32"></a>
<FONT color="green">033</FONT>     * The {@link JXPathContext} returned by {@link #getPageContext getPageContext()}<a name="line.33"></a>
<FONT color="green">034</FONT>     * provides access to all scopes via the PageContext.findAttribute()<a name="line.34"></a>
<FONT color="green">035</FONT>     * method.  Thus, an expression like "foo" will first look for the attribute<a name="line.35"></a>
<FONT color="green">036</FONT>     * named "foo" in the "page" context, then the "request" context, then<a name="line.36"></a>
<FONT color="green">037</FONT>     * the "session" one and finally in the "application" context.<a name="line.37"></a>
<FONT color="green">038</FONT>     * &lt;p&gt;<a name="line.38"></a>
<FONT color="green">039</FONT>     * If you need to limit the attibute lookup to just one scope, you can use the<a name="line.39"></a>
<FONT color="green">040</FONT>     * pre-definded variables "page", "request", "session" and "application".<a name="line.40"></a>
<FONT color="green">041</FONT>     * For example, the expression "$session/foo" extracts the value of the<a name="line.41"></a>
<FONT color="green">042</FONT>     * session attribute named "foo".<a name="line.42"></a>
<FONT color="green">043</FONT>     * &lt;p&gt;<a name="line.43"></a>
<FONT color="green">044</FONT>     * Following are some implementation details. There is a separate JXPathContext<a name="line.44"></a>
<FONT color="green">045</FONT>     * for each of the four scopes. These contexts are chained according to the<a name="line.45"></a>
<FONT color="green">046</FONT>     * nesting of the scopes.  So, the parent of the "page" JXPathContext is a<a name="line.46"></a>
<FONT color="green">047</FONT>     * "request" JXPathContext, whose parent is a "session" JXPathContext (that is<a name="line.47"></a>
<FONT color="green">048</FONT>     * if there is a session), whose parent is an "application" context.<a name="line.48"></a>
<FONT color="green">049</FONT>     * &lt;p&gt;<a name="line.49"></a>
<FONT color="green">050</FONT>     * The  XPath context node for each context is the corresponding object:<a name="line.50"></a>
<FONT color="green">051</FONT>     * PageContext, ServletRequest, HttpSession or ServletContext.  This feature can<a name="line.51"></a>
<FONT color="green">052</FONT>     * be used by servlets.  A servlet can use one of the methods declared by this<a name="line.52"></a>
<FONT color="green">053</FONT>     * class and work with a specific JXPathContext for any scope.<a name="line.53"></a>
<FONT color="green">054</FONT>     * &lt;p&gt;<a name="line.54"></a>
<FONT color="green">055</FONT>     * Since JXPath chains lookups for variables and extension functions, variables<a name="line.55"></a>
<FONT color="green">056</FONT>     * and extension function declared in the outer scopes are also available in<a name="line.56"></a>
<FONT color="green">057</FONT>     * the inner scopes.<a name="line.57"></a>
<FONT color="green">058</FONT>     * &lt;p&gt;<a name="line.58"></a>
<FONT color="green">059</FONT>     * Each  of the four context declares exactly one variable, the value of which<a name="line.59"></a>
<FONT color="green">060</FONT>     * is the corresponding object: PageContext, etc.<a name="line.60"></a>
<FONT color="green">061</FONT>     * &lt;p&gt;<a name="line.61"></a>
<FONT color="green">062</FONT>     * The  "session" variable will be undefined if there is no session for this<a name="line.62"></a>
<FONT color="green">063</FONT>     * servlet. JXPath does not automatically create sessions.<a name="line.63"></a>
<FONT color="green">064</FONT>     *<a name="line.64"></a>
<FONT color="green">065</FONT>     * @author Dmitri Plotnikov<a name="line.65"></a>
<FONT color="green">066</FONT>     * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $<a name="line.66"></a>
<FONT color="green">067</FONT>     */<a name="line.67"></a>
<FONT color="green">068</FONT>    public final class JXPathServletContexts {<a name="line.68"></a>
<FONT color="green">069</FONT>    <a name="line.69"></a>
<FONT color="green">070</FONT>        private static JXPathContextFactory factory;<a name="line.70"></a>
<FONT color="green">071</FONT>    <a name="line.71"></a>
<FONT color="green">072</FONT>        static {<a name="line.72"></a>
<FONT color="green">073</FONT>            JXPathIntrospector.registerDynamicClass(<a name="line.73"></a>
<FONT color="green">074</FONT>                    PageScopeContext.class,<a name="line.74"></a>
<FONT color="green">075</FONT>                    PageScopeContextHandler.class);<a name="line.75"></a>
<FONT color="green">076</FONT>            JXPathIntrospector.registerDynamicClass(<a name="line.76"></a>
<FONT color="green">077</FONT>                    PageContext.class,<a name="line.77"></a>
<FONT color="green">078</FONT>                    PageContextHandler.class);<a name="line.78"></a>
<FONT color="green">079</FONT>            JXPathIntrospector.registerDynamicClass(<a name="line.79"></a>
<FONT color="green">080</FONT>                    ServletContext.class,<a name="line.80"></a>
<FONT color="green">081</FONT>                    ServletContextHandler.class);<a name="line.81"></a>
<FONT color="green">082</FONT>            JXPathIntrospector.registerDynamicClass(<a name="line.82"></a>
<FONT color="green">083</FONT>                    ServletRequestAndContext.class,<a name="line.83"></a>
<FONT color="green">084</FONT>                    ServletRequestHandler.class);<a name="line.84"></a>
<FONT color="green">085</FONT>            JXPathIntrospector.registerDynamicClass(<a name="line.85"></a>
<FONT color="green">086</FONT>                    HttpSessionAndServletContext.class,<a name="line.86"></a>
<FONT color="green">087</FONT>                    HttpSessionHandler.class);<a name="line.87"></a>
<FONT color="green">088</FONT>            factory = JXPathContextFactory.newInstance();<a name="line.88"></a>
<FONT color="green">089</FONT>        }<a name="line.89"></a>
<FONT color="green">090</FONT>    <a name="line.90"></a>
<FONT color="green">091</FONT>        /**<a name="line.91"></a>
<FONT color="green">092</FONT>         * Returns a JXPathContext bound to the "page" scope. Caches that context<a name="line.92"></a>
<FONT color="green">093</FONT>         * within the PageContext itself.<a name="line.93"></a>
<FONT color="green">094</FONT>         * @param pageContext as described<a name="line.94"></a>
<FONT color="green">095</FONT>         * @return JXPathContext<a name="line.95"></a>
<FONT color="green">096</FONT>         */<a name="line.96"></a>
<FONT color="green">097</FONT>        public static JXPathContext getPageContext(PageContext pageContext) {<a name="line.97"></a>
<FONT color="green">098</FONT>            JXPathContext context =<a name="line.98"></a>
<FONT color="green">099</FONT>                (JXPathContext) pageContext.getAttribute(Constants.JXPATH_CONTEXT);<a name="line.99"></a>
<FONT color="green">100</FONT>            if (context == null) {<a name="line.100"></a>
<FONT color="green">101</FONT>                JXPathContext parentContext =<a name="line.101"></a>
<FONT color="green">102</FONT>                    getRequestContext(<a name="line.102"></a>
<FONT color="green">103</FONT>                        pageContext.getRequest(),<a name="line.103"></a>
<FONT color="green">104</FONT>                        pageContext.getServletContext());<a name="line.104"></a>
<FONT color="green">105</FONT>                context = factory.newContext(parentContext, pageContext);<a name="line.105"></a>
<FONT color="green">106</FONT>                context.setVariables(<a name="line.106"></a>
<FONT color="green">107</FONT>                    new KeywordVariables(<a name="line.107"></a>
<FONT color="green">108</FONT>                        Constants.PAGE_SCOPE,<a name="line.108"></a>
<FONT color="green">109</FONT>                        new PageScopeContext(pageContext)));<a name="line.109"></a>
<FONT color="green">110</FONT>                pageContext.setAttribute(Constants.JXPATH_CONTEXT, context);<a name="line.110"></a>
<FONT color="green">111</FONT>            }<a name="line.111"></a>
<FONT color="green">112</FONT>            return context;<a name="line.112"></a>
<FONT color="green">113</FONT>        }<a name="line.113"></a>
<FONT color="green">114</FONT>    <a name="line.114"></a>
<FONT color="green">115</FONT>        /**<a name="line.115"></a>
<FONT color="green">116</FONT>         * Returns a JXPathContext bound to the "request" scope. Caches that context<a name="line.116"></a>
<FONT color="green">117</FONT>         * within the request itself.<a name="line.117"></a>
<FONT color="green">118</FONT>         * @param request as described<a name="line.118"></a>
<FONT color="green">119</FONT>         * @param servletContext operative<a name="line.119"></a>
<FONT color="green">120</FONT>         * @return JXPathContext<a name="line.120"></a>
<FONT color="green">121</FONT>         */<a name="line.121"></a>
<FONT color="green">122</FONT>        public static JXPathContext getRequestContext(ServletRequest request,<a name="line.122"></a>
<FONT color="green">123</FONT>                ServletContext servletContext) {<a name="line.123"></a>
<FONT color="green">124</FONT>            JXPathContext context =<a name="line.124"></a>
<FONT color="green">125</FONT>                (JXPathContext) request.getAttribute(Constants.JXPATH_CONTEXT);<a name="line.125"></a>
<FONT color="green">126</FONT>            // If we are in an included JSP or Servlet, the request parameter<a name="line.126"></a>
<FONT color="green">127</FONT>            // will represent the included URL, but the JXPathContext we have<a name="line.127"></a>
<FONT color="green">128</FONT>            // just acquired will represent the outer request.<a name="line.128"></a>
<FONT color="green">129</FONT>            if (context != null) {<a name="line.129"></a>
<FONT color="green">130</FONT>                ServletRequestAndContext handle =<a name="line.130"></a>
<FONT color="green">131</FONT>                    (ServletRequestAndContext) context.getContextBean();<a name="line.131"></a>
<FONT color="green">132</FONT>                if (handle.getServletRequest() == request) {<a name="line.132"></a>
<FONT color="green">133</FONT>                    return context;<a name="line.133"></a>
<FONT color="green">134</FONT>                }<a name="line.134"></a>
<FONT color="green">135</FONT>            }<a name="line.135"></a>
<FONT color="green">136</FONT>    <a name="line.136"></a>
<FONT color="green">137</FONT>            JXPathContext parentContext = null;<a name="line.137"></a>
<FONT color="green">138</FONT>            if (request instanceof HttpServletRequest) {<a name="line.138"></a>
<FONT color="green">139</FONT>                HttpSession session =<a name="line.139"></a>
<FONT color="green">140</FONT>                    ((HttpServletRequest) request).getSession(false);<a name="line.140"></a>
<FONT color="green">141</FONT>                if (session != null) {<a name="line.141"></a>
<FONT color="green">142</FONT>                    parentContext = getSessionContext(session, servletContext);<a name="line.142"></a>
<FONT color="green">143</FONT>                }<a name="line.143"></a>
<FONT color="green">144</FONT>                else {<a name="line.144"></a>
<FONT color="green">145</FONT>                    parentContext = getApplicationContext(servletContext);<a name="line.145"></a>
<FONT color="green">146</FONT>                }<a name="line.146"></a>
<FONT color="green">147</FONT>            }<a name="line.147"></a>
<FONT color="green">148</FONT>            ServletRequestAndContext handle =<a name="line.148"></a>
<FONT color="green">149</FONT>                new ServletRequestAndContext(request, servletContext);<a name="line.149"></a>
<FONT color="green">150</FONT>            context = factory.newContext(parentContext, handle);<a name="line.150"></a>
<FONT color="green">151</FONT>            context.setVariables(<a name="line.151"></a>
<FONT color="green">152</FONT>                new KeywordVariables(Constants.REQUEST_SCOPE, handle));<a name="line.152"></a>
<FONT color="green">153</FONT>            request.setAttribute(Constants.JXPATH_CONTEXT, context);<a name="line.153"></a>
<FONT color="green">154</FONT>            return context;<a name="line.154"></a>
<FONT color="green">155</FONT>        }<a name="line.155"></a>
<FONT color="green">156</FONT>    <a name="line.156"></a>
<FONT color="green">157</FONT>        /**<a name="line.157"></a>
<FONT color="green">158</FONT>         * Returns a JXPathContext bound to the "session" scope. Caches that context<a name="line.158"></a>
<FONT color="green">159</FONT>         * within the session itself.<a name="line.159"></a>
<FONT color="green">160</FONT>         * @param session as described<a name="line.160"></a>
<FONT color="green">161</FONT>         * @param servletContext operative<a name="line.161"></a>
<FONT color="green">162</FONT>         * @return JXPathContext<a name="line.162"></a>
<FONT color="green">163</FONT>         */<a name="line.163"></a>
<FONT color="green">164</FONT>        public static JXPathContext getSessionContext(HttpSession session,<a name="line.164"></a>
<FONT color="green">165</FONT>                ServletContext servletContext) {<a name="line.165"></a>
<FONT color="green">166</FONT>            JXPathContext context =<a name="line.166"></a>
<FONT color="green">167</FONT>                (JXPathContext) session.getAttribute(Constants.JXPATH_CONTEXT);<a name="line.167"></a>
<FONT color="green">168</FONT>            if (context == null) {<a name="line.168"></a>
<FONT color="green">169</FONT>                JXPathContext parentContext = getApplicationContext(servletContext);<a name="line.169"></a>
<FONT color="green">170</FONT>                HttpSessionAndServletContext handle =<a name="line.170"></a>
<FONT color="green">171</FONT>                    new HttpSessionAndServletContext(session, servletContext);<a name="line.171"></a>
<FONT color="green">172</FONT>                context = factory.newContext(parentContext, handle);<a name="line.172"></a>
<FONT color="green">173</FONT>                context.setVariables(<a name="line.173"></a>
<FONT color="green">174</FONT>                    new KeywordVariables(Constants.SESSION_SCOPE, handle));<a name="line.174"></a>
<FONT color="green">175</FONT>                session.setAttribute(Constants.JXPATH_CONTEXT, context);<a name="line.175"></a>
<FONT color="green">176</FONT>            }<a name="line.176"></a>
<FONT color="green">177</FONT>            return context;<a name="line.177"></a>
<FONT color="green">178</FONT>        }<a name="line.178"></a>
<FONT color="green">179</FONT>    <a name="line.179"></a>
<FONT color="green">180</FONT>        /**<a name="line.180"></a>
<FONT color="green">181</FONT>         * Returns  a JXPathContext bound to the "application" scope. Caches that<a name="line.181"></a>
<FONT color="green">182</FONT>         * context within the servlet context itself.<a name="line.182"></a>
<FONT color="green">183</FONT>         * @param servletContext operative<a name="line.183"></a>
<FONT color="green">184</FONT>         * @return JXPathContext<a name="line.184"></a>
<FONT color="green">185</FONT>         */<a name="line.185"></a>
<FONT color="green">186</FONT>        public static JXPathContext getApplicationContext(<a name="line.186"></a>
<FONT color="green">187</FONT>                ServletContext servletContext) {<a name="line.187"></a>
<FONT color="green">188</FONT>            JXPathContext context =<a name="line.188"></a>
<FONT color="green">189</FONT>                (JXPathContext) servletContext.getAttribute(<a name="line.189"></a>
<FONT color="green">190</FONT>                    Constants.JXPATH_CONTEXT);<a name="line.190"></a>
<FONT color="green">191</FONT>            if (context == null) {<a name="line.191"></a>
<FONT color="green">192</FONT>                context = factory.newContext(null, servletContext);<a name="line.192"></a>
<FONT color="green">193</FONT>                context.setVariables(<a name="line.193"></a>
<FONT color="green">194</FONT>                    new KeywordVariables(<a name="line.194"></a>
<FONT color="green">195</FONT>                        Constants.APPLICATION_SCOPE,<a name="line.195"></a>
<FONT color="green">196</FONT>                        servletContext));<a name="line.196"></a>
<FONT color="green">197</FONT>                servletContext.setAttribute(Constants.JXPATH_CONTEXT, context);<a name="line.197"></a>
<FONT color="green">198</FONT>            }<a name="line.198"></a>
<FONT color="green">199</FONT>            return context;<a name="line.199"></a>
<FONT color="green">200</FONT>        }<a name="line.200"></a>
<FONT color="green">201</FONT>    }<a name="line.201"></a>




























































</PRE>
</BODY>
</HTML>
